T. W. Harris — Mount Bob or Mount Ida. 



237 



Si ace 



" Mt. Bob, so-called, is 

 a hill about one hundred 

 feet high, in the north- 

 west part of Claverack, 

 Columbia County. The 

 west side is very steep, 

 and a slope of debris of E|WRE '• 



the blue, compact lime- 

 stone, conceals a part of the rock of the same kind, which 

 rises about twenty feet in a mural escarpment, and dips to the 

 east, as is represented on Plate 38 [see fig. 1], where {a) is the 

 blue limestone, and (h) and (o) strata of gray fossiliferous lime- 

 stone like that of Becraft's Mountain. The slate underlies, 

 apparently unconformably." (Nat. Hist, of 1ST. Y., Part IY, 

 Geol. of First Dist, p. 351.) 



The name, " Mount Bob," has apparently now gone out of 

 use in the neighborhood, and the outlier is known in Hudson 

 as "Snake Hill," and among the farmers in the immediate 

 vicinity as " Mount Ida." The limestones form a wooded ele- 

 vation about half a mile long by a quarter broad, which rises 

 at the southern end in a steep cliff, one hundred feet or more 

 above the gently rolling, 

 drift-covered plain en- 

 circling it. but slopes 

 gently down to the 

 north. In structure, it 

 forms a fragment of a 

 northeastwardly plung- 

 ing syncline, and consists 

 of the three lower mem- 

 bers of the Lower 

 Helderberg group. The 

 great mass of the hill 

 consists of the 

 bedded strata 

 Tentaculite or 

 limestone, about 



t h i n - 

 of the 

 Bibbon 

 eighty 

 feet in thickness. No 

 fossils were found in 

 these but a few imper- 

 fect Leper ditiae. Above 

 this, and inside the crest 

 of the cliff, were about 

 twenty feet of the Lower 

 Pentamerus limestone, 

 coarse, gray and irregu- 

 larly bedded, in which a 

 few specimens of the 



MOUNT 'IDA. 



IN THE TOWN OF 

 CLAVERACK, XX, 



LEGEND^ 



= Hudson- River, 



shales. 

 - TenlaeuliCe. 

 limestone 

 • Lower Penrame- 

 /imeslone. 

 Sha/y /imescone. 

 Drift. 



